Showing papers on "Propulsion published in 1995"

Space Propulsion Analysis and Design

Abstract: List of Authors and Editors Preface Chapter 1 Introduction to Space Propulsion 1.1 Rocket Fundamentals 1.2 The Design Process Chapter 2 Mission Analysis 2.1 Keplerian Orbits 2.2 Orbit Perturbations 2.3 Orbit Maneuvering 2.4 Launch Windows 2.5 Orbit Maintenance 2.6 Earth to Orbit Chapter 3 Thermodynamics of Fluid Flow 3.1 Mass Transfer 3.2 Thermodynamic Relations (Energy and Entropy) 3.3 Thrust Equations 3.4 Heat Addition 3.5 HEat Transfer 3.6 Design Example-Cold-Gas Thruster Chapter 4 Thermochemistry 4.1 The Chemical Heat Source: Bond Energy 4.2 Thermochemistry Basics 4.3 Products of Combustion 4.4 Flame Temperature: The Available-Heat Method 4.5 Chemical Kinetics: The Speed of the Chemical Reactions 4.6 Combustion of Liquids vs.Solids 4.7 Propellant Characteristics and Their Implications 4.8 Key Thermochemical Parameters: The Bottom Line Chapter 5 Liquid Rocket Propulsion Systems 5.1 History 5.2 Design Process 5.3 Preliminary Design Decisions 5.4 System Sizing, Design, and Trade-off 5.5 Case Study Chapter 6 Solid Rocket Motors 6.1 Background 6.2 Design Process 6.3 Preliminary Sizing 6.4 Solid Rocket Propellants 6.5 Performance Prediction 6.6 Case Study Chapter 7 Hybrid Rocket Propulsion Systems 7.1 History 7.2 Hybrid-Motor Ballistics 7.3 Design Process 7.4 Preliminary Design Decisions 7.5 Performance Estimate 7.6 Preliminary Component Design 7.7 Case Study Chapter 8 Nuclear Rocket Propulsion Systems 8.1 Introduction 8.2 Design Process 8.3 Preliminary Design Decisions 8.4 Size the Reactor 8.5 Size the Radiation Shield 8.6 Evaluate Vehicle Operation 8.7 Case Study Chapter 9 Electric Rocket Propulsion Systems 9.1 History and Status 9.2 Design Process 9.3 Specify the Mission 9.4 Select an Electric Thruster 9.5 Select Space Power 9.6 Assess System Performance 9.7 Evaluate the System 9.8 Case Study Chapter 10 Mission Design Case Study 10.1 Define Mission Requirements 10.2 Develop Criteria to Evaluate and Select a System 10.3 Develop Alternative Mission Concepts 10.4 Define the Vehicle System and Select Potential Technologies 10.5 Develop Preliminary Designs for the Propulsion System 10.6 Assess Designs and Configurations 10.7 Compare Designs and Choose the Best Option Chapter 11 Advanced Propulsion Systems 11.1 Air-Augmented Rockets 11.2 Rocket Advancements 11.3 Nonrocket Advancements 11.4 Interstellar Flight Appendix A Units and Conversions Factors Appendix B Thermochemical Data for Selected Propellants Appendix C Launch Vehicles and Staging Index

Flight Mechanics of High-Performance Aircraft

Abstract: Preface Introduction Equations of motion Aerodynamic forces Propulsion systems Descent and glide performance Cruise performance Climb performance Turning performance Turning flight of jet aircraft Take-off and landing performance Performance of hypervelocity re-entry vehicles Appendices Selected bibliography Index.

Performance evaluation of a 250 kW switched reluctance starter generator

Abstract: This paper describes the system integration and performance evaluation testing of a high speed, 250 kW starter/generator [S/G] system used for starting and secondary electrical power extraction from an aircraft propulsion gas turbine. The effort described here is part a contract sponsored by the USAF, Wright Laboratories, WPAFB. The paper describes a switched reluctance [SR] machine which is operating both as a motor and generator in a speed range of 0 to 22,224 r.p.m. Additionally it is one of the highest rated motor/generator systems in the SR technology. The system employs two independent channels consisting of two groups of three phase windings, two three phase inverters, and two controllers and can provide two different power output buses for independent loading. The system hardware is described briefly followed by a detail description of the test results. These show some surprises with regards to single channel operating mode. A brief derivation and explanation of the findings is provided. The motor/generator system is planned to be part of a more electric aircraft power system.

Propulsion system with flexible/rigid oscillating fin

Abstract: The purpose of this paper is to describe the feasibility research on an oscillating fin propulsion control system as a vehicle actuator. The system is designed and constructed in order to be combined with ship models. Tank cruising tests are conducted to confirm the system's feasibility. As a result, several advantages of the oscillating fin system are found. A neural network is successfully applied for an identification of the ship model with the oscillating fin, and its effectiveness is confirmed. >

Aircraft having improved auto rotation and method for remotely controlling same

Abstract: A toy aircraft (10) includes a main body portion having a central hub member (22) and a plurality of wings (20). Each wing (20) of the plurality of wings is equally spaced about a central axis of rotation. The toy aircraft further includes a power source (18) carried by the aircraft, at least one motorized propulsion unit (14, 16) interconnected with the power source, and at least first and second propeller assemblies (48, 50) interconnected to the at least one motorized propulsion unit. The first and second propeller assemblies (48, 50) each include a plurality of blades (52, 54) arranged for rotation within a substantially horizontal plane. A preferred construction of the propellers includes a propeller shaft and a plurality of blades equally spaced about an axis of rotation defined by the propeller shaft. Each propeller is formed from foamed polystyrene. A preferred construction of a control system for controlling the flight of the toy aircraft includes a hand held remote control unit (82) and a receiver circuit (126) positioned on the toy aircraft.

Design Analysis Methodology for Solar-Powered Aircraft

Abstract: A methodology for conceptual design of solar-powered aircraft is described. The method is based on traditional design methodologies adapted to address the peculiar characteristics of solar-powered aircraft. The solar propulsion notation is applied to the analysis to create constraint diagrams that have takeoff wing loading ft = Wto/S as their independent variable, and the ratio of solar collector area to reference planform area R — Sce,,/S as their dependent variable. Constraints determined by the propulsion requirements for the design mission of the aircraft define a solution space on the constraint diagram. A design point is selected from within the solution space. Parametric estimates for component weights are then represented as wing loading portions. When these component wing loading portions are summed along with an expression for the required payload wing loading portion, they are equated to the design point wing loading. The resulting equation is solved for the required reference planform area, thus sizing the conceptual design. Three typical conceptual designs are described and analyzed, demonstrating the utility of the methodology.

Gasdynamic fusion propulsion system for space exploration

Abstract: An open-ended fusion system in which a high-density plasma is confined and heated to thermonuclear temperatures is examined as a potential high specific power propulsion device that can be used for space exploration. With a collision mean free path much smaller than a characteristic dimension of the system, the plasma behaves much like a continuous medium (fluid) for which the confinement time is drastically different from that which characterizes a typical fusion power reactor. Noting that fact and using an appropriate set of balance equations we derive an expression for the length of the rocket in terms of the plasma parameters required for certain propulsive capabilities. We find that a moderately sized system can produce large values of specific impulse and thrust that would allow a massive rocket to make a round-trip to Mars in months instead of years. By carrying out a preliminary engineering design we also identify those technological areas that must be developed before such a system can become practical. Many of these technologies are surprisingly not out of reach today.

Propulsion system and kit for hybrid motor vehicle

Abstract: A propulsion system for a vehicle comprising an electric motor, circuit breakers which switch field windings of the electric motor, as well as a cooling device which cools the field windings and the circuit breakers by its coolant circuit. The electric motor is realized in the form of a first modular unit which is mechanically functional in itself. The circuit breakers are assembled in at least one second modular unit, which is connected firmly to the first modular unit to form a propulsion unit. The individual modular units can be separated from one another and are connected to one another both by detachable electrical interface connections and also by detachable coolant interface connections. This construction makes it possible to selectively expand the propulsion unit by adding additional modular units, or in the event of the failure or malfunction of individual modular units to replace the modular units without having to replace the entire propulsion unit.

Design of a 100 kW switched reluctance motor for electric vehicle propulsion

Abstract: Low cost, high reliability, and competitive weight and efficiency combine to make the switched reluctance (SR) motor drive a strong candidate for application in future electric vehicle (EV) propulsion systems. This paper presents methods and results of a prototype SR motor design study. Finite element analysis and transient simulation results predict performance, efficiency, and weight that are competitive with existing EV propulsion systems, which have been tested in compact automobiles and small trucks. >

Auxiliary propulsion system for seagoing ships

Abstract: An auxiliary propulsion system that can be combined with a diesel engine to drive the shaft. A retrofittable diesel engine with a generator is installed to operate an electric motor. The electric motor is coupled to the shaft by means of a transmission with a flexible coupling and a clutch.

Combined azimuthing and tunnel auxillary thruster powered by integral and canned electric motor and marine vessel powered thereby

Abstract: An auxiliary thruster for a marine vessel. The auxiliary thruster includes a submersible propulsion unit which has a shroud with a propeller rotatably mounted therein. A canned electric motor is mounted between the propeller and the shroud for rotating the propeller to create thrust. A propulsion unit deploying and rotating mechanism is mounted on the hull and on the propulsion unit. The propulsion unit deploying and rotating mechanism is operable to extend the propulsion unit out of the hull and retract it into the hull and to rotate the propulsion unit to direct the thrust generated thereby in any desired direction when the thruster is in the deployed position. When the thruster is retracted, it is positioned with a tunnel extending transversely through the hull. Rotation of the propeller while in the retracted position generates laterally directed thrust through the tunnel.

Dual-fuel propulsion in single-stage Advanced Manned Launch System Vehicle

Abstract: As part of the United States Advanced Manned Launch System study to determine a follow-on, or complement, to the Space Shuttle, a reusable single-stage-to-orbit concept utilizing dual-fuel rocket propulsion has been examined Several dual-fuel propulsion concepts were investigated These include: a separate-engine concept combining Russian RD-170 kerosene-fueled engines with space shuttle main engine-derivative engines: the kerosene- and hydrogen-fueled Russian RD-701 engine; and a dual-fuel, dual-expander engine Analysis to determine vehicle weight and size characteristics was performed using conceptual-level design techniques A response-surface methodology for multidisciplinary design was utilized to optimize the dual-fuel vehicles with respect to several important propulsion-system and vehicle design parameters, in order to achieve minimum empty weight The tools and methods employed in the analysis process are also summarized In comparison with a reference hydrogen- fueled single-stage vehicle, results showed that the dual-fuel vehicles were from 10 to 30% lower in empty weight for the same payload capability, with the dual-expander engine types showing the greatest potential

Underwater two phase ramjet engine

Abstract: An underwater two-phase ramjet propulsion unit includes an inlet (104) for receiving a flow of water, a compressed gas injector (132, 134) for injecting compressed gas into the flow of water, a mixing chamber (106) for mixing the compressed gas with the water to provide a two-phase flow of working fluid, and a nozzle (108) for accelerating the two-phase working fluid to generate a two-phase jet. The propulsion unit can be implemented with fixed geometry or variable geometry. The propulsion unit includes a supersonic gas injector (132) as well as a subsonic gas injector (134). The propulsion unit includes a control system (110) for controlling the compressor (122), supersonic gas injector (132), subsonic gas injector (134), the geometry of the unit, and the direction of the thrust vector.

Advanced propulsion for geostationary orbit insertion and north-south station keeping

Abstract: Solar electric propulsion (SEP) technology is currently being used for geostationary satellite station keeping to increase payload mass. Analyses show that advanced electric propulsion technologies can be used to obtain additional increases in payload mass by using these same technologies to perform part of the orbit transfer. In this work three electric propulsion technologies are examined at two power levels for an Atlas 2AS class spacecraft. The on-board chemical propulsion apogee engine fuel is reduced to allow the use of electric propulsion. A numerical optimizer is used to determine the chemical burns which will minimize the electric propulsion transfer time. Results show that for a 1550 kg Atlas 2AS class payload, increases in net mass (geostationary satellite mass less wet propulsion system mass) of 150 to 800 kg are possible using electric propulsion for station keeping, advanced chemical engines for part of the transfer, and electric propulsion for the remainder of the transfer. Trip times are between one and four months.

Integrated high speed MAGLEV system

Abstract: An integrated MAGLEV (Magnetic Levitated Vehicle) system consists of permanent or preferably superconducting vehicle-mounted magnets which interact with both active and induced track-based currents. The magnets on the vehicle which are used for propulsion serve the dual purpose of realizing both levitation and lateral stabilization (guidance). The contribution offered by this invention is that it is able to provide propulsion, levitation, and guidance using a single type of track-based coil interacting with a singular type of magnetic field which is affixed to the vehicle. The realization of multiple functions with a single coil reduces the cost and enhances the efficiency of this MAGLEV system. In the main embodiment of this invention, propulsion currents are injected into brushes sliding along brush contact surfaces on the rail. Motion induced currents in the coils realize both the necessary levitation and guidance forces for the vehicle. The propulsion system is basically a linear DC motor and requires no power handling along the track. Necessary operating power can either be carried on the vehicle or collected by a third rail pickup system. All coils in the track are supported by a reinforced recycled plastic matrix (polyvinyl fiberglass) or similar material.

Analysis of the combined Maglev levitation, propulsion, and guidance system

Abstract: An analysis of a Japanese Maglev system that uses only one set of coils in the guideway for combined levitation, propulsion, and guidance functions is presented. This preliminary study, using the dynamic circuit approach, indicates that the system is very promising. >

Vector control board for an electric vehicle propulsion system motor controller

Abstract: A vector control board (46) for an electric vehicle propulsion system motor controller comprising a microcontroller (100) for generating torque requests, a digital signal processor (200) for receiving the torque requests from the microcontroller and for generating phase voltage signals in accordance with the torque requests, and a digital gate array (300) for receiving the phase voltage signals from the digital signal processor and for generating gate drive signals from the phase voltage signals.

Wide speed range turboshaft study

Abstract: NASA-Lewis and NASA-Ames have sponsored a series of studies over the last few years to identify key high speed rotorcraft propulsion and airframe technologies. NASA concluded from these studies that for near term aircraft with cruise speeds up to 450 kt, tilting rotor rotorcraft concepts are the most economical and technologically viable. The propulsion issues critical to tilting rotor rotorcraft are: (1) high speed cruise propulsion system efficiency and (2) adequate power to hover safely with one engine inoperative. High speed cruise propeller efficiency can be dramatically improved by reducing rotor speed, yet high rotor speed is critical for good hover performance. With a conventional turboshaft, this wide range of power turbine operating speeds would result in poor engine performance at one or more of these critical operating conditions. This study identifies several wide speed range turboshaft concepts, and analyzes their potential to improve performance at the diverse cruise and hover operating conditions. Many unique concepts were examined, and the selected concepts are simple, low cost, relatively low risk, and entirely contained within the power turbine. These power turbine concepts contain unique, incidence tolerant airfoil designs that allow the engine to cruise efficiently at 51 percent of the hover rotor speed. Overall propulsion system efficiency in cruise is improved as much as 14 percent, with similar improvements in engine weight and cost. The study is composed of a propulsion requirement survey, a concept screening study, a preliminary definition and evaluation of selected concepts, and identification of key technologies and development needs. In addition, a civil transport tilting rotor rotorcraft mission analysis was performed to show the benefit of these concepts versus a conventional turboshaft. Other potential applications for this technology are discussed.

Material-handling vehicle

Abstract: A material-handling vehicle comprising a structure having a ground engageable propulsion device, a loader arm, having a longitudinal axis, mounted at the rear of the structure for up and down swinging movement, an operator's cab disposed on the structure on one side of the loader arm longitudinal axis and an engine mounted on the structure to provide power for the swinging movement of the arm and propulsion of the vehicle, wherein the engine is located on one side of the loader arm longitudinal axis and the engine has an output shaft and the engine is transversely disposed with its output shaft transverse to the vehicle.

Near-optimal propulsion-system operation for an air-breathing launch vehicle

Abstract: A methodology for determining the near-optimal operation of the propulsion system of hybrid air-breathing launch vehicles is derived. The method is based on selecting propulsion-system modes and parameters that maximize a certain performance function. This function is derived from consideration of the energy-state model of the aircraft equations of motion. The vehicle model reflects the many interactions and complexities of the multimode air-breathing and rocket engine systems proposed for launch-vehicle use. The method is used to investigate the optimal throttle switching of air-breathing and rocket engine modes, and to investigate the desirability of using liquid-oxygen augmentation in air-breathing engine cycles, the oxygen either carried from takeoff or collected in flight. It is found that the air-breathing engine is always at full throttle, and that the rocket is on full at takeoff and at very high Mach numbers, but off otherwise. Augmentation of the air-breathing engine with stored liquid oxygen is beneficial, but only marginally so.

Vehicle having two axially spaced relatively movable wheels

Abstract: A parallel vehicle includes three main control systems. The first controls the position and angle of the two parallel wheels relative to a fixed chassis, enabling the wheels to be moved outwardly and inwardly and the camber varied for greater stability, aerodynamic effect, or turning. This first system may be mechanically or hydraulically actuated, but preferably is controlled by a pair of control members whose position relative to the chassis corresponds to the desired position of the wheels relative to the chassis in order to provide an intuitive control mechanism. The second system is the propulsion system which may, for example, take the form of a derailleur drive of the type used in bicycles, but with power from the propulsion system being transmitted to the wheels via a rotating cable and individual gearboxes for each wheel which permit the direction of the wheels to be reversed. Finally, a braking system includes a braking mechanism which can be individually controlled to separately brake the wheels for steering purposes or to brake both of the wheels at the same time.

STOL/VTOL free wing aircraft with variable pitch propulsion means

Abstract: A VTOL/STOL free wing aircraft includes a free wing having wings on opposite sides of a fuselage connected to one another respectively for free rotation about a spanwise access. Improved control upon landing of the aircraft is achieved by utilizing a variable pitch propulsion system, enabling the pitch of the propeller to be varied corresponding to the speed of the aircraft and angle of approach upon descent.

Fusion energy in space propulsion

Abstract: Principles of Fusion Energy Utilization in Space Propulsion High-Performance Fusion Rocket for Manned Space Missions An Antiproton Catalyzed Inertial Fusion Propulsion System Comparison of Fusion/Antiproton Propulsion Systems for Interplanetary Travel An Antiproton Driver for Internal Confinement Fusion Propulsion From SSTO to Saturn's Moons - Superperformance Fusion Propulsion for Practical Spaceflight Innovative Technology for an Inertial Electrostatic Confinement (IEC) Fusion Propulsion Unit Fusion Plasma Thruster Using a Dense Plasma Focus Device Performance of Fusion-Fission Hybrid Nuclear Rocket Engine Magnetic Control of Fission Plasmas The Outer Solar System and the Human Future.

Solid-fuel, liquid oxidizer hybrid rocket turbopump auxiliary engine

Abstract: A propulsion thruster (10) includes a solid-fuel, liquid-oxidizer main rocket engine (11), a tank (22) of liquid oxygen, and a turbine (32)-driven pump (30) for pumping liquid oxygen to the main engine. A solid-fuel, liquid-oxidizer auxiliary engine (40) has its oxidizer input port (50) coupled to the output (30b) of the turbopump, for generating drive fluids for the turbine (32) of the turbopump. The temperature of the turbine drive fluids is reduced to prevent damage to the turbine, and the mass flow rate is increased, by injecting water from a tank (60) into the drive fluids at the output (48) of the auxiliary engine (40). Starting is enhanced by preventing cooling of the solid fuel by the liquid oxidizer, which is accomplished by applying gaseous oxygen from a tank (90) to the oxidizer input port (50) of the auxiliary engine (40).

A transient model of the RL10A-3-3A rocket engine

Abstract: RL10A-3-3A rocket engines have served as the main propulsion system for Centaur upper stage vehicles since the early 1980's. This hydrogen/oxygen expander cycle engine continues to play a major role in the American launch industry. The Space Propulsion Technology Division at the NASA Lewis Research Center has created a computer model of the RL10 engine, based on detailed component analyses and available test data. This RL10 engine model can predict the performance of the engine over a wide range of operating conditions. The model may also be used to predict the effects of any proposed design changes and anticipated failure scenarios. In this paper, the results of the component analyses are discussed. Simulation results from the new system model are compared with engine test and flight data, including the start and shut-down transient characteristics.

Aircraft with jet flap propulsion

Abstract: In an aircraft (1) according to the invention the engine drives a blower and the compressed air is used to increase the lift of the wing (18) and the canard (22) using jet flap propulsion. The airfoil profile has maximum thickness just forward of the control surface device (12) which has large included trailing edge angle and large leading edge radius. The control surface device hinge (17) is positioned close to the mean line (19) of the plane, and air slots (10) in the plane are blowing the control surface device.

Electric Propulsion Space Experiment (ESEX) flight qualification and operations

Abstract: : The Electric Propulsion Space Experiment (ESEX) is one of eight experiments being launched in early 1997 on the Advanced Research and Global Observation Satellite (ARGOS). ESEX has successfully completed flight qualification and is awaiting integration. ESEX will be the first flight of a high power arcjet propulsion subsystem. The arcjet experiment will nominally fire 10 times for a total of 150 minutes. The flight data will include measurements of both performance and spacecraft integration issues, as well as ground and space observations of the arcjet plume.